Marantz AV7005 - serious ground loop hum

darien87

darien87

Audioholic Spartan
Are you using Internet Explorer? :D

If so (like me), you need to turn on the Compatibility View for all websites.

Menu Bar ---> Tool ---> Compatibility View Setting ---- > display for all sites
YESSSSSSSSSSSSS!

That did it. Thanks for the help.
 
darien87

darien87

Audioholic Spartan
I'm about done with this thing. Emotiva recommended attaching a ground wire from the back of the AV7005 to the screw on the wall socket but that didn't help. I got rid of the XLR cables and went all RCA to both amps and the noise decreased by about half. It's not as loud but still audible enough to be annoying.

Here's the weird thing, last night while I was messing around with the system, the wife turned on the microwave which is in the kitchen about 30' to the right of the processor and the buzz got louder. Marantz thinks this points to an issue with my home's wiring. I would think the wiring would be good. The house is only 3 years old, but who knows. But I'm about ready to give up and just go back to the UMC-1.
 
Irvrobinson

Irvrobinson

Audioholic Spartan
I'm about ready to give up and just go back to the UMC-1.
That sounds like a really good idea. The problems you're having with the Marantz, which apparently are widespread, are inexcusable, and I wouldn't want something so poorly designed in my system.
 
adk highlander

adk highlander

Sith Lord
I feel your pain. I tried so many fixes the first couple of weeks I had mine that I nearly went insane. Then when the second one was worse than the first I knew something was up. Like you I had no issues until this was in the mix. I had a Denon 2708, Pioneer Elite 72vx and an Onkyo PR-SC885 all dead silent. So many are supremely confident that there is no design issue because they don't have the problem and I don't want to continually sound like the squeaky wheel. My solution was XLR cables and using a cheater plug my amp. I have almost 0 hum and you have to be closer than 2 feet to hear the buzz. When my projector is running and I am seated I don't hear it at all. It took me over 6 months to get over it and let it go. I really wanted to solve it the "right" way but a cheater plug was the only real fix. I have a dedicated circuit for my gear and very close to the panel so I know it is not my electrical wiring.
 
RichB

RichB

Audioholic Field Marshall
Yep, ground loop sucks. Especially, if you need more than one circuit.
It can come in on a USB cable for cripes sake :p

- Rich
 
Adam

Adam

Audioholic Jedi
Talk of this Marantz having grounding problems popped into my head when I was taking the cover off of my Marantz NR1604 yesterday. Both the 1604 and 1504 models have a crushable copper washer underneath one of the screws that holds the cover on. The only thing that I could think of for why it would be there is to improve the electrical connection. Thing is - it would seem to only improve the connection between the screw and the cover, and the screw just goes through a threaded hole in the internal frame.

Just curious if anyone here knows why that washer is actually there, and if it is for an electrical connection, if it might help with the issues on the 7005?
 
darien87

darien87

Audioholic Spartan
My solution was XLR cables and using a cheater plug my amp. I have almost 0 hum and you have to be closer than 2 feet to hear the buzz. When my projector is running and I am seated I don't hear it at all. It took me over 6 months to get over it and let it go. I really wanted to solve it the "right" way but a cheater plug was the only real fix.
I bought a cheater plug but I didn't try it because the plug for my first 7005 was 2-prong so it didn't make sense to me. But the cord the guy gave me with the 2nd one is 3 prong. But the connection at the back of the 7005 is still 2 prong so I wouldn't think that would make any difference but I guess it couldn't hurt to give it a shot.
 
adk highlander

adk highlander

Sith Lord
I use the cheater on my ATI amplifier (which is a 3 prong 15amp cord) not on the AV7005. I did try a variety of power cords on the AV7005 but none made any difference.
 
darien87

darien87

Audioholic Spartan
I use the cheater on my ATI amplifier (which is a 3 prong 15amp cord) not on the AV7005. I did try a variety of power cords on the AV7005 but none made any difference.
Gotcha. But I've got 3 amps connected to the thing and they all buzz.

The IT guy at my work gave me a Oneac regulator to try. It goes between the wall and the 7005 and isolates it. He says if it still buzzes when it's hooked into the Oneac then it must be something in the speaker wiring.
 
adk highlander

adk highlander

Sith Lord
I had three connected as well but 2 of them were for other zones and made no difference to the theater if there were connected or not. I found that comment from Marantz odd about mixing RCA and balanced.

Let me know about the Oneac. I'm going to be laid up for a couple of weeks with too much free time and can see myself possibly selling off the Marantz and going back to Onkyo/Integra.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I bought a cheater plug but I didn't try it because the plug for my first 7005 was 2-prong so it didn't make sense to me. But the cord the guy gave me with the 2nd one is 3 prong. But the connection at the back of the 7005 is still 2 prong so I wouldn't think that would make any difference but I guess it couldn't hurt to give it a shot.
Yeah, I am almost certain the cheater plug on the amps would work.

Or place the cheater plug at the beginning of the chain - right at the Ground Fault outlet.
 
darien87

darien87

Audioholic Spartan
Yeah, I am almost certain the cheater plug on the amps would work.

Or place the cheater plug at the beginning of the chain - right at the Ground Fault outlet.
Well everything other than the EP4000 is connected to the Belkin power center. I guess I could try the cheater plug at the Belkin and see if that fixes it.
 
j_garcia

j_garcia

Audioholic Jedi
It's weird how these things really seem to be hit or miss.
Both of yours were open box though, so it could be a common thing and people have returned them as a result (regardless of what Magnolia/BB told you). By now, I would have ordered a UMC200 :) It is less than the 7005.

OH and another thing you should have already, and I created one when I had power issues in my last house, if you don't already have a circuit map of your house - make one. Find out which outlets are on the same circuits. Hum/buzz can come from fluorescent lights, anything with a fan or motor, etc... so having the 7005 on the same circuit as some devices can also cause this. The fact that the UMC-1 didn't do it though, says to me it is something in how the grounding is designed in the Marantz that means it probably isn't going to work for you.
 
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P

PENG

Audioholic Slumlord
adk is right, the cheater on the Marantz would not work but if your Emo amp is truly 3 prong grounded then it may just work. You are a very patient person, I would have got a refund on this thing by now and moved on to something else already.
 
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